I have a 24 row 1250 planter with factory liquid fertilizer run off of my pro 700. Recently I am not able to hold my rate. I am trying to put 5 gpa down. My rates will fall suddenly and will not work, then I get a max flow warning for my liquid pump. If I leave it off for a round, it will work for a round. It will continue to work until I get to the end and turn around, when I turn around and start going the rate instantly falls and goes to zero. I've cleaned the filters, they were clean. I've checked the oil in the pump, and made sure there is 10 psi in the air manifold deal on the pump, as the book says. Any ideas?